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The Big University football team, a member of the Southeastern Conference (SEC), brings in over $100 million a year in revenue, including TV rights, ticket sales, and bowl games. Seats to a game cost well over $100, and coaches are paid millions of dollars (more than anyone else at Big U, including the president). However, despite enormous revenues, universities and their football teams are considered not-for-profit organizations and pay no taxes on the $100+ million their football programs bring in. Should a university football program be allowed to exist as a not-for-profit organization?
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Jen started a new sustainability-oriented business six years ago, making single-serve coffee pods out of recyclable paper, rather than plastic. Her company, Jen’s Pod, is now experiencing rapid growth. Jen started her company as an LLC but has been considering making a decision to incorporate. What are some of the advantages of changing to a C corporation?
 Some close family members decide it would be a good idea to buy a house in the college town and then rent it out to students, with you also living there and actively managing it. Assuming you and your family buy it, what form of business would you select?
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Jackson owns and runs a small computer repair business, a sole proprietorship, out of his home, with one employee. He also goes to small businesses at their locations, mostly cleaning viruses and doing other small maintenance tasks and repairs. A family physician’s office calls him in for a repair. He sends his employee to do the repair. Unknown to him, his employee makes a copy of patients’ personal information and sells it on the dark web. Jackson ends up being sued, and the plaintiffs ask the court to allow them to access Jackson’s personal, nonbusiness bank account that also has his spouse’s funds in the account. Can the plaintiffs take that money?


2.15: Water - Water’s Solvent Properties
- Explain why some molecules do not dissolve in water.
Water’s Solvent Properties
Water, which not only dissolves many compounds but also dissolves more substances than any other liquid, is considered the universal solvent. A polar molecule with partially-positive and negative charges, it readily dissolves ions and polar molecules. Water is therefore referred to as a solvent: a substance capable of dissolving other polar molecules and ionic compounds. The charges associated with these molecules form hydrogen bonds with water, surrounding the particle with water molecules. This is referred to as a sphere of hydration, or a hydration shell, and serves to keep the particles separated or dispersed in the water.
When ionic compounds are added to water, individual ions interact with the polar regions of the water molecules during the dissociation process, disrupting their ionic bonds. Dissociation occurs when atoms or groups of atoms break off from molecules and form ions. Consider table salt (NaCl, or sodium chloride): when NaCl crystals are added to water, the molecules of NaCl dissociate into Na + and Cl – ions, and spheres of hydration form around the ions. The positively-charged sodium ion is surrounded by the partially-negative charge of the water molecule’s oxygen; the negatively-charged chloride ion is surrounded by the partially-positive charge of the hydrogen in the water molecule.
Since many biomolecules are either polar or charged, water readily dissolves these hydrophilic compounds. Water is a poor solvent, however, for hydrophobic molecules such as lipids. Nonpolar molecules experience hydrophobic interactions in water: the water changes its hydrogen bonding patterns around the hydrophobic molecules to produce a cage-like structure called a clathrate. This change in the hydrogen-bonding pattern of the water solvent causes the system’s overall entropy to greatly decrease, as the molecules become more ordered than in liquid water. Thermodynamically, such a large decrease in entropy is not spontaneous, and the hydrophobic molecule will not dissolve.
Key Points
- Water dissociates salts by separating the cations and anions and forming new interactions between the water and ions.
- Water dissolves many biomolecules, because they are polar and therefore hydrophilic.
Key Terms
- dissociation : The process by which a compound or complex body breaks up into simpler constituents such as atoms or ions, usually reversibly.
- hydration shell : The term given to a solvation shell (a structure composed of a chemical that acts as a solvent and surrounds a solute species) with a water solvent; also referred to as a hydration sphere.


17.6: Building an Organization for the Future
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What is talent acquisition, and how can it create a competitive advantage for a company?
We’ve discussed some of the key focus areas that human resource management professionals need to address to ensure that employees are performing their roles well and are being fairly rewarded for their contributions. We haven’t yet addressed how we think about where these employees come from—Whom do we hire? What skills do we need now and in the future? Where will we even look for these employees? What are some best practices? Talent acquisition is the area within human resource management that defines the strategy for selection, recruiting, and hiring processes, and helps the organization fight the “ war for talent ” during good times and bad.
Hiring strong talent is a key source of competitive advantage for a company, yet so many companies do it poorly. Often, the recruiting and hiring processes happen reactively—someone leaves the organization and then people scramble to fill the gap. Very few companies take a longer-term, proactive approach and work to create a strategic plan for talent acquisition. In the article “The Definitive Guide to Recruiting in Good Times and Bad” (Fernandez-Araoz, Groysberg, Nohria, HBR, 2009), the authors advocate for a rigorous and strategic recruiting process that includes the following critical actions:
- Anticipate your future leadership needs based on your strategic business plan.
- Identify the specific competencies required in each position you need to fill.
- Develop a sufficiently large candidate pool.
In organizations today, there are often pieces of the talent acquisition process that are outsourced to external recruiters, as opposed to being managed internally by human resources employees. While outsourcing specific searches is not an issue, there must be internal HR/talent acquisition employees responsible for creating the overall strategic plan for the recruiting function. Contract recruiters may then take responsibility for a piece of the overall process by leveraging the strategy and competencies that the HR team puts forth.
Recruiting and hiring of high-level leadership candidates has special risks and rewards associated with it. The risk that a key leadership position is vacant or becoming vacant poses a risk to the organization if it is left open for too long. These high-level positions are often harder to fill, with fewer candidates being available and the selection of the right talent being so critical to the organization’s future. The reward, however, is that with due diligence and clear goals and competencies/skills defined for the position, the HR/talent acquisition professional can create a competitive advantage through the recruitment of key high-level talent.
The following best practices illustrate the key steps for effective recruiting of key leadership hires. Both human resources and business leadership should partner to discuss and define each of the elements to ensure alignment and support of the recruiting plan and process (Definitive Guide to Recruiting, HBR, 2009).
Anticipate your needs. Every two to three years there should be a review of high-level leadership requirements based on the strategic plan. Some of the questions to answer here are:
- How many people will we need, and in what positions, in the next few years?
- What will the organizational structure look like?
- What must our leadership pipeline contain today to ensure that we find and develop tomorrow’s leaders?
Specify the job. For each leadership position identified, specify competencies needed in each role. For example:
- Job-based: What capabilities will the job require?
- Team-based: Will the applicant need to manage political dynamics?
- Firm-based: What resources (supporting, talent, technology) will the organization need to provide the person who fills this role?
Develop the pool. Cast a wide net for candidates by asking suppliers, customers, board members, professional service provides, and trusted insiders for suggestions. It helps to start this process even before you have a role that you’re hiring for. During succession planning and talent discussions internally, it helps to start making of list of internal and external contacts and potential candidates before the need arises.
Assess the candidates. Have the hiring manager, the second-level manager, and the top HR manager conduct a “behavioral event interview” with each candidate. Candidates will describe experiences they’ve had that are like situations they’ll face in the organization. Gain an understanding of how the candidate acted and the reasoning behind their actions. Make sure to evaluate a broad range of references to ask about results the candidate achieved.
Close the deal. Once you have chosen the final candidate, you can increase the chance that the job offer will be accepted by:
- Sharing passion about the company and role, and showing genuine interest in the candidate
- Acknowledging the opportunities and challenges of the role, differentiating the opportunities at your organization from those of your competitor
- Striking a creative balance between salary, bonuses, and other long-term incentives
Integrate the newcomer. It is important to integrate new hires into the company’s culture:
- During the first few months, have the managers and the HR team check in with each new hire.
- Assign a mentor (star employee) to provide ongoing support to each new hire.
- Check in with the new hire to ensure that they are getting enough support, and inquire about what other support might be needed. Ensure that new hires are adequately building new relationships throughout the organization.
Refer to Table \(\PageIndex{1}\): Hiring Top-Level Executives, adapted from “The Definitive Guide to Recruiting in Good Times and Bad,” from the article “Hiring Top Executives: A Comprehensive End-to-End Process,” Harvard Business Review , May 2009.
By following these best practices, human resources and business leadership can ensure that the new hire is integrating well and has the best possible start in the new role. Talent acquisition is a key element of any human resource management program, and the right process can mean the difference between a poor hire and a distinct competitive advantage gained through top talent.
concept check
- How can we ensure a more successful integration of the new hire?


15.8: Pornography
Pornography is the ‘portrayal of sexual subject matter for the purpose of arousal.” Pornography has been around for as long as human beings have been creating art. Before the internet, film, photography, and the printing press, there were people creating sexual imagery for the purpose of arousal, as depicted by ancient drawing, painting and sculpture.
The professional porn industry is often referred to as the “adult industry.” Child pornography, or any sexual imagery depicting people under the age of 18, is illegal in the United States. We also see a lot of what is known as “amateur porn” on the Internet today. This refers to pornography that someone is creating on their own, not as a job, but often for their own enjoyment, and for others to enjoy as well. There are big differences between professional porn created by the adult industry and amateur pornography.
Professional porn does not represent reality, nor is it meant to. It is a fantasy. Just as in other professional films, many techniques are used to create that fantasy. Lighting, makeup, camera angles, photoshopping are all used to create visual imagery and to enhance how people look. As far as obtaining and maintaining erections, there are fluffers off camera (people to help with erections).  Keeping this in mind, it is best not to compare oneself or one’s sex life with pornography (LAD Bible, 2022).
For many young people today, pornography is being used as an unofficial sex education.
Many sex educators believe it is important youth receive education about pornography, but not be shamed for being curious about it, or for receiving pleasure from it. Education should include teaching that it is illegal to consume pornography if you’re under the age of 18, that although the naked human body is not shameful, they should not take or share naked pictures of themselves or others, or pictures or videos that are sexual in nature. This could be considered child pornography, and there could be serious legal and social consequences for this.
The largest online adult content sites average about 3 trillion monthly visitors. This is more than popular sites such as Amazon, Netflix and Reddit. The annual revenue from pornography is anywhere from $6-$15 billion in the United States (Grant, 2020). Clearly, there is a high demand for pornography, and the industry is not going anywhere. However, it is going through changes. Due to the Covid-19 pandemic, when everything shut down at first, many porn actors began working from home, offering their own content online. Some predict that this trend will continue to have an effect on the adult industry, as more people opt to work for themselves (Grant, 2020).
By Sam Zia, LMFT
In the Summer of 2013, the adult film industry was in flux. The industry was transitioning from the distribution of traditional, physical forms of media, such as DVD and VHS, to online streaming services. Los Angeles had just passed Measure B (requiring condoms to be used on porn sets) the previous year, a decision that was in the process of being appealed. The argument from the adult film industry, in defense of not needing condoms in porn, was based around the idea that with mandated, frequent testing of performers (every two weeks, at most 4 weeks), they could “police themselves,” and prevent major outbreaks of STIs.
This idea was put to the test that August, when an adult film star tested positive for HIV. The ripple effect was immediate. The industry called for a moratorium on all shooting, allowing for any performers testing positive to be removed from the talent pool before resuming production/filming. Over a period of a month, four performers were found to have contracted HIV. It was determined that none of the cases of transmission occurred on-set (the last known case of on-set HIV transmission occurred in 2004). This incident, however, highlighted a glaring problem within the Adult Film industry. Although testing is mandated by production companies on shoots featuring a man and women, or two women, some companies that shoot scenes involving two men do not require STD/STI testing. Despite this, the only times the industry had to shut down filming since 2013, was in 2017, when three performers tested positive for HIV, and in 2020, with the Covid-19 pandemic.
Since the 2013 HIV outbreak, the industry has continued to evolve. Many production companies left Los Angeles County, settling in surrounding counties, or Las Vegas. With the Covid-19 pandemic, shooting shut down temporarily, with many adult film stars creating their own websites and webcamming pages to continue to make money. However, since the industry has had experience with transmissible illnesses, it was not long before production companies adapted to the need for more stringent testing, and filming resumed.
My name is Lance and I began doing sex work when I was 29, and it has been my career for the last 12 years. During the 2008 recession, I was laid off from my retail management job, so I decided to explore my passion for massage therapy, and went to school to learn more technique. I was quite comfortable with my body and a very sexual person, and had previously attended a few all-male massage workshops that were rooted in The Body Electric School, which seeks to connect the erotic and the sacred.
Doing erotic work felt like a very natural extension to my massage work, though there was certainly a learning and growth curve.
One of the questions I often get from others is how do I have sex with someone that I’m not attracted to, and in all honesty, it took some effort in the beginning. I’ve observed that most people tend to look at themselves and rather than focus on all that is beautiful and blessed we focus on what is “imperfect” and we tend to place that judgment on other people as well. As I grew to love myself more, I began to see others differently. While in the beginning, focusing on what was attractive about a client was something I had to make a conscious effort to do, it soon became natural. I soon began to realize that the vulnerability and trust they showed me was not only beautiful but was also sacred and spiritual.
As a white, cisgender male at 6’3” I do recognize my privilege in this industry. I don’t have to be nearly as cautious or do as much screening of my clients as cis & trans women, and I’m rarely the focus of legal persecution, which unfairly equates sex work with human trafficking, as some feel that through their pious efforts, they need to “save” people from their work.
 I have had the honor to share erotic energy with a man in his 70’s, who was recently widowed and had never been with a man, though had been longing for it for 50+ years. I’ve laid in a hospice bed and held a man dying of brain cancer, because his best friend wanted him to experience one last time naked with a man (I’m crying while I type this).
Though everyone’s experience and motivation in this industry is different, for me, bringing deep intimacy in every session is my hope and intention. One can have sex and an erotic experience without much intimacy, but it’s intimacy that really gets to the heart and soul and, that’s where I hope to reside with my clients, even if it’s just for an hour or so. As I like to say Sex Work is Soul Work.
Because many types of sexuality work that engages with the body are currently illegal in most of the United States, workers face additional risk of legal prosecution for doing their job. While the issue remains complicated, this new pair of laws, FOSTA, the Fight Online Sex Trafficking Act, and SESTA, the Stop Enabling Sex Traffickers Act essentially pose greater risk to sex workers who rely on the internet to make a living.
Watch the following for more information, and also read FOSTA-SESTA, a law intended to curb sex trafficking, threatens the internet's future - Vox


¡Ajá!
bebé
quiquiriquí
¡Achú!
An important question
¿Cómo se escribe ____? ( How do you spell ____?)
____ se escribe __-__-__-__. ( ____ is spelled __-__-__-__. )
- How do I type special characters?
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Add texts here. Do not delete this text first.
The tilde over the letter ‘n’, the accent marks that are sometimes needed over vowels, and the upside-down question mark and exclamation point are all symbols that don’t appear in the standard English-language qwerty keyboard. How can you type them? There are several ways, depending on your device and the program you’re using.
Most programs will have a menu option to Insert Special Character, and you can scroll through until you find the one you want to use. The Windows operating system lets you toggle between different language keyboards, and the one for Spanish has keys for the ñ, for example (it’s where the semicolon is on the qwerty keyboard), and shortcuts for putting accent marks on vowels (tap the apostrophe and then e to produce é, for example). Here’s a youtube video explaining how it works: https://youtu.be/tHx20SBc4jI . The Apple operating systems have similar keyboard shortcuts (hold down option and e, then tap e, to produce é, for example). Newer macOS computers also let you press and hold a vowel to choose the accented version. Here’s a youtube video explaining how to type special characters on a Mac: https://youtu.be/VaeqmJi2kAw . On an iOS device, you tap and hold the character to bring up a menu of special characters.Click here to see the access codes for your device: https://sip.la.psu.edu/blp/tech-support/accents .
Exploring things you never knew your devices could do will be part of the fun of learning Spanish!
Contributors and Attributions
- Typebar in closeup. Authored by : Csabi Elter. Located at : https://unsplash.com/photos/IIDxzNru2GY . License : Other . License Terms : https://unsplash.com/license
- El alfabeto. Authored by : SUNY Oneonta with Lumen Learning. Provided by : SUNY Oneonta. License : CC BY: Attribution


35.9: The Nervous System
- Summarize the nervous system
Introduction to the Nervous System
The nervous system of higher vertebrates (the group that includes humans) is a widely-distributed communication and processing network that serves controlling functions over other organ systems. It possesses a key function in the orientation of the individual; controls its behavior, motor function, and sensory processing; and contains mechanisms to store information. A classification of the nervous system can be performed under different aspects. The anatomical compartmentalization of its components defines the classical approach. Two major divisions of the nervous system are the central nervous system (CNS) and the peripheral nervous system (PNS).
Central Nervous System
The vertebrate central nervous system (CNS) contains the brain and the spinal cord. The brain contains structurally- and functionally-defined regions. In mammals, these include the cortex (which can be broken down into four primary functional lobes: frontal, temporal, occipital, and parietal), basal ganglia, thalamus, hypothalamus, limbic system, cerebellum, and brainstem; although structures in some of these designations overlap. While functions may be primarily localized to one structure in the brain, most complex functions, such as language and sleep, involve neurons in multiple brain regions. The spinal cord is the information superhighway, connecting the brain with the rest of the body through the peripheral nerves. It transmits sensory and motor input and also controls motor reflexes.
The CNS is covered with three layers of protective coverings called meninges (from the Greek word for membrane). The outermost layer is the dura mater (Latin for “hard mother”). As the Latin name suggests, the primary function for this thick layer is to protect the brain and spinal cord. The dura mater also contains vein-like structures that carry blood from the brain back to the heart. The middle layer is the web-like arachnoid mater. The last layer is the pia mater (Latin for “soft mother”), which directly contacts and covers the brain and spinal cord like plastic wrap. The space between the arachnoid and pia maters is filled with cerebrospinal fluid (CSF). CSF is produced by a tissue called the choroid plexus in fluid-filled compartments in the CNS called ventricles. The brain floats in CSF, which acts as a cushion and shock absorber, making the brain neutrally buoyant. CSF also functions to circulate chemical substances throughout the brain and into the spinal cord.
Peripheral Nervous System
The peripheral nervous system consists of nerves that are connected to the brain (cranial nerves) and nerves that are connected to the spinal cord (spinal nerves). The main function of the PNS is to connect the central nervous system (CNS) to the limbs and organs, essentially serving as a communication relay between the brain and the extremities. Unlike the CNS, the PNS is not protected by the bone of spine and skull. Nor does it have a barrier between itself and the blood, leaving it exposed to toxins and mechanical injuries.
The autonomic nervous system, also part of the peripheral nervous system, controls internal body functions that are not under conscious control. For example, when a prey animal is chased by a predator, the autonomic nervous system automatically increases the rate of breathing and the heartbeat. It dilates the blood vessels that carry blood to the muscles, releases glucose from the liver, and makes other adjustments to provide for the sudden increase in activity. When the animal has escaped and is safe once again, the nervous system slows down all these processes and resumes all the normal body activities, such as the digestion of food.
Contributions and Attributions
- central nervous system. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/central_nervous_system . License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44749/latest...ol11448/latest . License : CC BY: Attribution
- Anatomy and Physiology of Animals/Nervous System. Provided by : Wikibooks. Located at : en.wikibooks.org/wiki/Anatomy...Nervous_System . License : CC BY-SA: Attribution-ShareAlike
- General Anatomy/Nervous System. Provided by : Wikibooks. Located at : en.wikibooks.org/wiki/General...Nervous_System . License : CC BY-SA: Attribution-ShareAlike
- Peripheral nervous system. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Periphe...nervous_system . License : CC BY-SA: Attribution-ShareAlike
- meninges. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/meninges . License : CC BY-SA: Attribution-ShareAlike
- peripheral nervous system. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/periphe...rvous%20system . License : CC BY-SA: Attribution-ShareAlike
- cerebrospinal fluid. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/cerebrospinal_fluid . License : CC BY-SA: Attribution-ShareAlike
- autonomic nervous system. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/autono...nervous_system . License : CC BY-SA: Attribution-ShareAlike
- Meninges-en. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Meninges-en.svg . License : Public Domain: No Known Copyright
- Central nervous system. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Ce...ous_system.svg . License : Public Domain: No Known Copyright
Key Points
- The central nervous system consists of the brain, which controls complex body functions, and the spinal cord, which transmits signals from the brain to the rest of the body.
- The brain and spinal cord are covered by three layers of meninges, or protective coverings: the dura mater, the arachnoid mater, and the pia mater.
- Cerebrospinal fluid surrounds the brain, cushioning it and providing shock absorption to prevent damage.
- The peripheral nervous system is made up of nerves that originate within the brain and spinal cord; it serves to relay information from the central nervous system to all parts of the body.
- The autonomic system controls involuntary bodily functions, such as heart rate, breathing, digestion, and blood vessel dilation.
Key Terms
- central nervous system : in vertebrates, that part of the nervous system comprising the brain and spinal cord
- cerebrospinal fluid : a clear bodily fluid that occupies the subarachnoid space in the brain (between the skull and the cerebral cortex), and which acts as a cushion or buffer for the cortex
- meninges : the three membranes that envelop the brain and spinal cord
- autonomic nervous system : the part of the nervous system that regulates the involuntary activity of the heart, intestines and glands
- peripheral nervous system : the part of the nervous system which is not the central nervous system


4.7: Poisson Distribution
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The Poisson distribution is popular for modelling the number of times an event occurs in an interval of time or space. It is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since the last event.
two main characteristics of a Poisson experiment
- The Poisson probability distribution gives the probability of a number of events occurring in a fixed interval of time or space if these events happen with a known average rate and independently of the time since the last event. For example, a book editor might be interested in the number of words spelled incorrectly in a particular book. It might be that, on the average, there are five words spelled incorrectly in 100 pages. The interval is the 100 pages.
- The Poisson distribution may be used to approximate the binomial if the probability of success is "small" (such as 0.01) and the number of trials is "large" (such as 1,000). You will verify the relationship in the homework exercises. \(n\) is the number of trials, and \(p\) is the probability of a "success."
The random variable \(X =\) the number of occurrences in the interval of interest.
Example \(\PageIndex{1}\)
The average number of loaves of bread put on a shelf in a bakery in a half-hour period is 12. Of interest is the number of loaves of bread put on the shelf in five minutes. The time interval of interest is five minutes. What is the probability that the number of loaves, selected randomly, put on the shelf in five minutes is three?
Solution
Let \(X =\) the number of loaves of bread put on the shelf in five minutes. If the average number of loaves put on the shelf in 30 minutes (half-hour) is 12, then the average number of loaves put on the shelf in five minutes is \(\left(\frac{5}{30}\right)(12) = 2\) loaves of bread.
The probability question asks you to find \(P(x = 3)\).
Exercise \(\PageIndex{1}\)
The average number of fish caught in an hour is eight. Of interest is the number of fish caught in 15 minutes. The time interval of interest is 15 minutes. What is the average number of fish caught in 15 minutes?
Answer
\(\left(\frac{15}{60}\right)(8) = 2\) fish
Example \(\PageIndex{2}\)
A bank expects to receive six bad checks per day, on average. What is the probability of the bank getting fewer than five bad checks on any given day? Of interest is the number of checks the bank receives in one day, so the time interval of interest is one day. Let \(X =\) the number of bad checks the bank receives in one day. If the bank expects to receive six bad checks per day then the average is six checks per day. Write a mathematical statement for the probability question.
Answer
\(P(x < 5)\)
Exercise \(\PageIndex{2}\)
An electronics store expects to have ten returns per day on average. The manager wants to know the probability of the store getting fewer than eight returns on any given day. State the probability question mathematically.
Answer
\(P(x < 8)\)
Example \(\PageIndex{3}\)
You notice that a news reporter says "uh," on average, two times per broadcast. What is the probability that the news reporter says "uh" more than two times per broadcast. This is a Poisson problem because you are interested in knowing the number of times the news reporter says "uh" during a broadcast.
- What is the interval of interest?
- What is the average number of times the news reporter says "uh" during one broadcast?
- Let \(X =\) ____________. What values does X take on?
- The probability question is \(P(\)______\()\).
Solutions
- one broadcast
- 2
- Let \(X =\) the number of times the news reporter says "uh" during one broadcast. \[x = 0, 1, 2, 3, \dotsc\]
- \(P(x > 2)\)
Exercise \(\PageIndex{3}\)
An emergency room at a particular hospital gets an average of five patients per hour. A doctor wants to know the probability that the ER gets more than five patients per hour. Give the reason why this would be a Poisson distribution.
Answer
This problem wants to find the probability of events occurring in a fixed interval of time with a known average rate. The events are independent.
Notation for the Poisson: \(P =\) Poisson Probability Distribution Function
\[X \sim P(\mu)\]
Read this as "\(X\) is a random variable with a Poisson distribution." The parameter is \(\mu\) (or \(\lambda\)); \(\mu\) (or \(\lambda) =\) the mean for the interval of interest.
Example \(\PageIndex{4}\)
Leah's answering machine receives about six telephone calls between 8 a.m. and 10 a.m. What is the probability that Leah receives more than one call in the next 15 minutes?
Solution
Let \(X\) = the number of calls Leah receives in 15 minutes. (The interval of interest is 15 minutes or \(\frac{1}{4}\) hour.)
\[x = 0, 1, 2, 3, \dotsc\]
If Leah receives, on the average, six telephone calls in two hours, and there are eight 15 minute intervals in two hours, then Leah receives
\(\left(\frac{1}{8}\right)(6) = 0.75\) calls in 15 minutes, on average. So, \(\mu = 0.75\) for this problem.
\(X \sim P(0.75)\)
Find \(P(x > 1)\). \(P(x > 1) = 0.1734\) (calculator or computer)
- Press 1 – and then press 2 nd DISTR.
- Arrow down to poissoncdf. Press ENTER.
- Enter (.75,1).
- The result is \(P(x > 1) = 0.1734\).
The TI calculators use \(\lambda\) (lambda) for the mean.
The probability that Leah receives more than one telephone call in the next 15 minutes is about 0.1734:
\(P(x > 1) = 1 − \text{poissoncdf}(0.75, 1)\).The graph of \(X \sim P(0.75)\) is:
The y -axis contains the probability of \(x\) where \(X =\) the number of calls in 15 minutes.
Exercise \(\PageIndex{4}\)
A customer service center receives about ten emails every half-hour. What is the probability that the customer service center receives more than four emails in the next six minutes? Use the TI-83+ or TI-84 calculator to find the answer.
Answer
\(P(x > 4) = 0.0527\)
Example \(\PageIndex{5}\)
According to Baydin, an email management company, an email user gets, on average, 147 emails per day. Let \(X =\) the number of emails an email user receives per day. The discrete random variable \(X\) takes on the values \(x = 0, 1, 2 \dotsc\). The random variable \(X\) has a Poisson distribution: \(X \sim P(147)\). The mean is 147 emails.
- What is the probability that an email user receives exactly 160 emails per day?
- What is the probability that an email user receives at most 160 emails per day?
- What is the standard deviation?
Solutions
- \(P(x = 160) = \text{poissonpdf}(147, 160) \approx 0.0180\)
- \(P(x \leq 160) = \text{poissoncdf}(147, 160) \approx 0.8666\)
- Standard Deviation \(= \sigma = \sqrt{\mu} = \sqrt{147} \approx 12.1244\)
Exercise \(\PageIndex{5}\)
According to a recent poll by the Pew Internet Project, girls between the ages of 14 and 17 send an average of 187 text messages each day. Let \(X =\) the number of texts that a girl aged 14 to 17 sends per day. The discrete random variable \(X\) takes on the values \(x = 0, 1, 2 \dotsc\). The random variable \(X\) has a Poisson distribution: \(X \sim P(187)\). The mean is 187 text messages.
- What is the probability that a teen girl sends exactly 175 texts per day?
- What is the probability that a teen girl sends at most 150 texts per day?
- What is the standard deviation?
Answer
- \(P(x = 175) = \text{poissonpdf}(187, 175) \approx 0.0203\)
- \(P(x \leq 150) = \text{poissoncdf}(187, 150) \approx 0.0030\)
- Standard Deviation \(= \sigma = \sqrt{\mu} = \sqrt{187} \approx 13.6748\)
Example \(\PageIndex{6}\)
Text message users receive or send an average of 41.5 text messages per day.
- How many text messages does a text message user receive or send per hour?
- What is the probability that a text message user receives or sends two messages per hour?
- What is the probability that a text message user receives or sends more than two messages per hour?
Solutions
- Let \(X =\) the number of texts that a user sends or receives in one hour. The average number of texts received per hour is \(\frac{41.5}{24} \approx 1.7292\).
- \(X \sim P(1.7292)\), so \(P(x = 2) = \text{poissonpdf}(1.7292, 2) \approx 0.2653\)
- \(P(x > 2) = 1 – P(x \leq 2) = 1 – \text{poissoncdf}(1.7292, 2) \approx 1 – 0.7495 = 0.2505\)
Exercise \(\PageIndex{6}\)
Atlanta’s Hartsfield-Jackson International Airport is the busiest airport in the world. On average there are 2,500 arrivals and departures each day.
- How many airplanes arrive and depart the airport per hour?
- What is the probability that there are exactly 100 arrivals and departures in one hour?
- What is the probability that there are at most 100 arrivals and departures in one hour?
Answer
- Let \(X =\) the number of airplanes arriving and departing from Hartsfield-Jackson in one hour. The average number of arrivals and departures per hour is \(\frac{2,500}{24} \approx 104.1667\).
- \(X \sim P(104.1667)\), so \(P(x = 100) = \text{poissonpdf}(104.1667, 100) \approx 0.0366\).
- \(P(x \leq 100) = \text{poissoncdf}(104.1667, 100) \approx 0.3651\).
The Poisson distribution can be used to approximate probabilities for a binomial distribution. This next example demonstrates the relationship between the Poisson and the binomial distributions. Let \(n\) represent the number of binomial trials and let \(p\) represent the probability of a success for each trial. If \(n\) is large enough and \(p\) is small enough then the Poisson approximates the binomial very well. In general, \(n\) is considered “large enough” if it is greater than or equal to 20. The probability \(p\) from the binomial distribution should be less than or equal to 0.05. When the Poisson is used to approximate the binomial, we use the binomial mean \(\mu = np\). The variance of \(X\) is \(\sigma^{2} = \sqrt{\mu}\) and the standard deviation is \(\sigma = \sqrt{\mu}\). The Poisson approximation to a binomial distribution was commonly used in the days before technology made both values very easy to calculate.
Example \(\PageIndex{7}\)
On May 13, 2013, starting at 4:30 PM, the probability of low seismic activity for the next 48 hours in Alaska was reported as about 1.02%. Use this information for the next 200 days to find the probability that there will be low seismic activity in ten of the next 200 days. Use both the binomial and Poisson distributions to calculate the probabilities. Are they close?
Answer
Let \(X\) = the number of days with low seismic activity.
Using the binomial distribution:
- \(P(x = 10) = \text{binompdf}(200, .0102, 10) \approx\ 0.000039\)
Using the Poisson distribution:
- Calculate \(\mu = np = 200(0.0102) \approx 2.04\)
- \(P(x = 10) = \text{poissonpdf}(2.04, 10) \approx 0.000045\)
We expect the approximation to be good because \(n\) is large (greater than 20) and \(p\) is small (less than 0.05). The results are close—both probabilities reported are almost 0.
Exercise \(\PageIndex{7}\)
On May 13, 2013, starting at 4:30 PM, the probability of moderate seismic activity for the next 48 hours in the Kuril Islands off the coast of Japan was reported at about 1.43%. Use this information for the next 100 days to find the probability that there will be low seismic activity in five of the next 100 days. Use both the binomial and Poisson distributions to calculate the probabilities. Are they close?
Answer
Let \(X =\) the number of days with moderate seismic activity.
Using the binomial distribution: \(P(x = 5) = \text{binompdf}(100, 0.0143, 5) \approx 0.0115\)
Using the Poisson distribution:
- Calculate \(\mu = np = 100(0.0143) = 1.43\)
- \(P(x = 5) = \text{poissonpdf}(1.43, 5) = 0.0119\)
We expect the approximation to be good because \(n\) is large (greater than 20) and \(p\) is small (less than 0.05). The results are close—the difference between the values is 0.0004.
References
- “ATL Fact Sheet,” Department of Aviation at the Hartsfield-Jackson Atlanta International Airport, 2013. Available online at www.atl.com/about-atl/atl-factsheet/ (accessed May 15, 2013).
- Center for Disease Control and Prevention. “Teen Drivers: Fact Sheet,” Injury Prevention & Control: Motor Vehicle Safety, October 2, 2012. Available online at http://www.cdc.gov/Motorvehiclesafet...factsheet.html (accessed May 15, 2013).
- “Children and Childrearing,” Ministry of Health, Labour, and Welfare. Available online at http://www.mhlw.go.jp/english/policy...ing/index.html (accessed May 15, 2013).
- “Eating Disorder Statistics,” South Carolina Department of Mental Health, 2006. Available online at http://www.state.sc.us/dmh/anorexia/statistics.htm (accessed May 15, 2013).
- “Giving Birth in Manila: The maternity ward at the Dr Jose Fabella Memorial Hospital in Manila, the busiest in the Philippines, where there is an average of 60 births a day,” theguardian, 2013. Available online at www.theguardian.com/world/gal...471900&index=2 (accessed May 15, 2013).
- “How Americans Use Text Messaging,” Pew Internet, 2013. Available online at pewinternet.org/Reports/2011/...in-Report.aspx (accessed May 15, 2013).
- Lenhart, Amanda. “Teens, Smartphones & Testing: Texting volum is up while the frequency of voice calling is down. About one in four teens say they own smartphones,” Pew Internet, 2012. Available online at www.pewinternet.org/~/media/F...nd_Texting.pdf (accessed May 15, 2013).
- “One born every minute: the maternity unit where mothers are THREE to a bed,” MailOnline. Available online at http://www.dailymail.co.uk/news/arti...thers-bed.html (accessed May 15, 2013).
- Vanderkam, Laura. “Stop Checking Your Email, Now.” CNNMoney, 2013. Available online at management.fortune.cnn.com/20...our-email-now/ (accessed May 15, 2013).
- “World Earthquakes: Live Earthquake News and Highlights,” World Earthquakes, 2012. www.world-earthquakes.com/ind...thq_prediction (accessed May 15, 2013).
Review
A Poisson probability distribution of a discrete random variable gives the probability of a number of events occurring in a fixed interval of time or space, if these events happen at a known average rate and independently of the time since the last event. The Poisson distribution may be used to approximate the binomial, if the probability of success is "small" (less than or equal to 0.05) and the number of trials is "large" (greater than or equal to 20).
Formula Review
\(X \sim P(\mu)\) means that \(X\) has a Poisson probability distribution where \(X =\) the number of occurrences in the interval of interest.
\(X\) takes on the values \(x = 0, 1, 2, 3, \dotsc\)
The mean \(\mu\) is typically given.
The variance is \(\sigma = \mu\), and the standard deviation is
\[\sigma = \sqrt{\mu}\].
When \(P(\mu)\) is used to approximate a binomial distribution, \(\mu = np\) where \(n\) represents the number of independent trials and \(p\) represents the probability of success in a single trial.
Use the following information to answer the next six exercises: On average, a clothing store gets 120 customers per day.
Exercise \(\PageIndex{8}\)
Assume the event occurs independently in any given day. Define the random variable \(X\).
Exercise \(\PageIndex{9}\)
What values does \(X\) take on?
Answer
0, 1, 2, 3, 4, …
Exercise \(\PageIndex{10}\)
What is the probability of getting 150 customers in one day?
Exercise \(\PageIndex{11}\)
What is the probability of getting 35 customers in the first four hours? Assume the store is open 12 hours each day.
Answer
0.0485
Exercise \(\PageIndex{12}\)
What is the probability that the store will have more than 12 customers in the first hour?
Exercise \(\PageIndex{13}\)
What is the probability that the store will have fewer than 12 customers in the first two hours?
Answer
0.0214
Exercise \(\PageIndex{14}\)
Which type of distribution can the Poisson model be used to approximate? When would you do this?
Use the following information to answer the next six exercises: On average, eight teens in the U.S. die from motor vehicle injuries per day. As a result, states across the country are debating raising the driving age.
Exercise \(\PageIndex{15}\)
Assume the event occurs independently in any given day. In words, define the random variable \(X\).
Answer
\(X =\) the number of U.S. teens who die from motor vehicle injuries per day.
Exercise \(\PageIndex{16}\)
\(X \sim\) _____(_____,_____)
Exercise \(\PageIndex{17}\)
What values does \(X\) take on?
Answer
\(0, 1, 2, 3, 4, \dotsc\)
Exercise \(\PageIndex{18}\)
For the given values of the random variable \(X\), fill in the corresponding probabilities.
Exercise \(\PageIndex{19}\)
Is it likely that there will be no teens killed from motor vehicle injuries on any given day in the U.S? Justify your answer numerically.
Answer
No
Exercise \(\PageIndex{20}\)
Is it likely that there will be more than 20 teens killed from motor vehicle injuries on any given day in the U.S.? Justify your answer numerically.
Glossary
- Poisson Probability Distribution
-
a discrete random variable (RV) that counts the number of times a certain event will occur in a specific interval; characteristics of the variable:
- The probability that the event occurs in a given interval is the same for all intervals.
- The events occur with a known mean and independently of the time since the last event.
\[\left(e^{-\mu}\right)\frac{\mu^{x}}{x!}\]
. The Poisson distribution is often used to approximate the binomial distribution, when \(n\) is “large” and \(p\) is “small” (a general rule is that \(n\) should be greater than or equal to 20 and \(p\) should be less than or equal to 0.05).


8.2: Stages of Relationships
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In intimate relationships, such as friendships and romantic relationships, communication is key, as it is through communication that we begin, develop, maintain, and dissolve relationships. In this section, we will describe four stages of intimate relationships and present communication theories that help us better understand our communicative interactions during these stages.
Beginning Stage
In order to form a relationship with another person, we first must come into contact with them, whether it be face-to-face or through a mediated platform, such as a social networking site, dating site, or an app. In the beginning stage of the relationships, we interact with the other person to increase our knowledge about them and decide if we want to continue forming the relationship. During this stage, two communication theories can help us understand why we form relationships: Uncertainty Reduction Theory and Attraction Theory.
Uncertainty Reduction Theory
Uncertainty Reduction Theory, also known as Initial Interaction Theory, can help us better understand the communicative behaviors involved in first interactions. The theory posits that, when interacting, people need information about the other party in order to reduce their uncertainty. Uncertainty is a sense of “not knowing” that people find to be unpleasant and seek to reduce through interpersonal communication. The theory identifies two types of uncertainty: cognitive and behavioral. Cognitive uncertainty pertains to the level of uncertainty associated with our thoughts (beliefs and attitudes) of each other in the situation.[4] Behavioral uncertainty is related to people’s actions and whether or not they fit our expectations for what we consider to be “normal” or not. Behavior that is outside of acceptable norms may increase uncertainty and reduce the chances for future interaction.
There are three types of strategies people may use to seek information about someone: passive (observing from afar), active (indirectly seeking information about the other), and interactive (seeking a direct exchange with the other). In gaining this information people are better able to predict the other’s behavior and resulting actions, all of which are crucial in the development of any relationship. The initial interaction of strangers can also be broken down into individual stages—the entry stage (when people engage in behavioral norms), the personal stage (when people tend to explore the other’s beliefs, attitudes, morals, etc.), and the exit stage
Attraction Theory
Attraction Theory posits that three factors influence our attraction to others: their similarity to us, their proximity, and their interpersonal attractiveness (Alberts, Nakayama, & Martin, 2016).
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Similarity:
Have you ever heard the phrase ‘birds of a feather flock together’? Similarity is often an important determinant in whether or not we find someone else attractive. Research has shown that people are more strongly attracted to others who are similar in physical appearance, beliefs, attitudes, and who share similar co-cultural identities and backgrounds. Conversely, differences in these categories can lead to dislike or avoidance of others (Berkowitz, 1974; Singh & Ho, 2000; Bryne, London, & Reeves, 1968). -
Proximity:
Proximity, how geographically and physically close we are to another person, also plays a role in relationship formation (Alberts, Nakayama, & Martin, 2016). In order to form a relationship with someone, we first have to come into contact with them. Historically, it was difficult to meet others outside of our geographical area. However, technology has transformed how we meet and carry out relationships since we are no longer constrained by geographic barriers. From social networking sites to mobile apps, we now have the ability to connect with anyone, anytime, anywhere. Mediated platforms have become a way to connect to others to start both romantic and platonic relationships because it is easier to connect with those who share similar interests and have similar relationship goals (such as hooking up, long-term relationship, non-monogamous relationship, etc). Still, when it comes to relationships, such as friendships, proximity is still one of the biggest determinants. Generally speaking, we are more likely to form relationships with people we actually meet face-to-face through, for example, being in the same class or working at the same place. -
Interpersonal Attractiveness:
We communicate more with people we are attracted to (McCroskey & McCain, 1974, p. 261). Interpersonal attractiveness encompasses three components: physical attractiveness, social attractiveness, and task attractiveness (MrCroskey, McCrowskey, & Richmond, 2006). Physical attractiveness is the degree to which we find another person’s physical features to be pleasing. Social attractiveness encompasses characteristics such as friendliness, charisma, and warmth; whereas task attractiveness pertains to attraction based on another’s abilities, skills, and/or talents. (Alberts, Nakayama, & Martin, 2016, p. 192).
Developing Stage
The next stage of relationships is the development stage during which our communication and interactions with the other person increases. To help us better understand this stage, four communication theories explain the who, why, and how of relationship development, as well as some differences between face-to-face and mediated-communication relationship development. The theories are: Interpersonal Needs Theory, Social Exchange Theory, Social Penetration Theory, and Hyperpersonal Communication Theory.
Interpersonal Needs Theory
Interpersonal Needs Theory posits that we are likely to develop relationships with other people if they meet one or more of three basic interpersonal need. These three need operate on a continuum and are influenced by context (Schutz, W., 1966).
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Affection:
People have a need for affection and appreciation. This need can be fulfilled through family, friendships, and romantic relationships. and Some people may crave many intimate relationships while other may choose to limit them. -
Control:
The need for control pertains to our ability to influence people, events, and their environments. Just like with affection, some people crave less control of people, events, and their environments while others crave more. For example, in a friendship, one person may want to be the one who always decides where to hang out and the other may be okay with that. However, the need for control can also vary by individual levels of motivation and context. For example, in a friendship we may place less importance on who calls the shots, while in the workplace we may seek greater influence on others and events. -
Belonging:
Finally, people desire to be around other people. Similar to our other two needs, the need for belonging exists on a continuum, can vary between individuals and is based on context. Some people may limit their interactions or choose smaller groups while others may crave more frequent interactions and attention.
Social Penetration Theory
A key to understanding Social Penetration Theory is to first understand self-disclosure. Self-disclosure is the process of revealing information about yourself to others that is not readily known by them, and it plays a key role in the formation of relationships. As we get to know someone we engage in a reciprocal process of self-disclosure. The amount of self-disclosure changes in breadth and depth as the relationship develops. Depth pertains to how personal the information is where as breath refers to the range of topics that are discussed. Degrees of self-disclosure range from relatively safe (revealing your hobbies or musical preferences) to more personal topics (illuminating fears, dreams for the future, or fantasies). Typically, as relationships deepen and trust is established, self-disclosure increases in both breadth and depth. We tend to disclose facts about ourselves first (I am a Biology major), then move towards opinions (I feel the war is wrong), and finally disclose feelings (I’m sad that you said that).
An important aspect of self-disclosure is the rule of reciprocity. This rule states that self-disclosure between two people works best in a back and forth fashion. When you tell someone something personal, you probably expect them to do the same. When one person reveals more than another, there can be an imbalance in the relationship because the one who self discloses more may feel vulnerable as a result of sharing more personal information.
Social Exchange Theory
Social Exchange Theory essentially entails a weighing of the costs and rewards in a given relationship (Harvey & Wenzel, 2006). Rewards are outcomes that we get from a relationship that benefit us in some way, such as companionship and/or social support. Costs can range from granting favors to providing emotional support. When we do not receive the outcomes or rewards that we think we deserve, then we may negatively evaluate the relationship, or at least a given exchange or moment in the relationship, and view ourselves as being under-benefited, which could lead to the eventual termination of the relationship. In an equitable relationship, costs and rewards are balanced, which usually leads to a positive evaluation of the relationship and satisfaction. Ultimately, relationships are more likely to succeed when there is satisfaction and commitment, meaning that we are pleased in a relationship intrinsically or by the rewards we receive.
Hyperpersonal Communication Theory
Hyperpersonal Communication Theory examines how mediated-communication enables communicative advantages and how this can lead to intense, overly intimate, and idealized relationships. People who meet online have a better opportunity to make a favorable impression on the other. This is because we can decide which information we would like to share about ourselves by controlling our self-presentations online (O’Sullivan, 2002), giving us the power to disclose only our ‘good’ traits. According to Walther, we have the ability to present ourselves in highly strategic and highly positive ways. The asynchronous nature of mediated-communication also allows us to think about texts or emails before sending them. Further, prior to sending messages, we can rewrite them for clarity, sense, and relevancy. Online asynchronous experiences allow for “optimal and desirable” communication, ensuring that the messages are of high quality.
Additionally, because mediated communication enables us to selectively present ourselves, the exchange lacks ‘contrary cues,’. In face-to-face interactions, we would pay attention to not just what the person says, but also what they do. For example, the other person interacting rudely with a server over dinner would influence our overall impression of that person. However, we don’t necessarily get to see how a person acts with others and the world around them in mediated-communication relationships, which can lead to an idealized view of that other person that may not live up to reality.
Maintaining Stage
The next stage of relationships is the maintaining stage where the relationship is in a prolonged or continued state of relatively mutual satisfaction for both parties. During this stage, Relational Dialectics Theory can help us better understand how relationships are sustained.
Relational Dialectics
One way we can better understand our personal relationships is by understanding the notion of relational dialectics. Baxter (1988) describes three relational dialectics that are constantly at play in interpersonal relationships: autonomy-connection, novelty-predictability, and openness-closedness. Essentially, they are a continuum of needs for each participant in a relationship that must be negotiated by those involved.
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Autonomy-Connection:
refers to our need to have close connection with others as well as our need to have our own space and identity. We may miss our romantic partner when they are away but simultaneously enjoy and cherish that alone time. When you first enter a romantic relationship, you probably want to be around the other person as much as possible. As the relationship grows, you likely begin to desire fulfilling your need for autonomy, or alone time.  -
Novelty-Predictability:
is the idea that we desire predictability as well as spontaneity in our relationships. In every relationship, we take comfort in a certain level of routine as a way of knowing what we can count on the other person in the relationship. Such predictability provides a sense of comfort and security. However, it requires balance with novelty to avoid boredom. An example of balance might be friends who get together every Saturday for brunch, but make a commitment to always try new restaurants each week. -
Openness-Closedness:
refers to the desire to be open and honest with others while at the same time not wanting to reveal everything about yourself to someone else. One’s desire for privacy does not mean they are shutting out others. It is a normal human need. We tend to disclose the most personal information to those with whom we have the closest relationships. However, even these people do not know everything about us. As the old saying goes, “We all have skeletons in our closet,” and that’s okay.
It’s important to note that these dialectics are dynamic and that our needs change over time. At times, we may even hold what appear to be contradictory needs. Relationship dissatisfaction is caused when our needs are not being met in a relationship, or when the other person falls on the opposite end of the continuum. For example, if you fall higher on the autonomy end of the continuum and your romantic partner falls higher on the connection end, you may end up feeling smothered or think that the other person is ‘clingy.’ Conversely, the other person may feel like you never want to spend time with them and thus are not as interested in the relationship as they are. Because negative feelings and miscommunication can arise as a result of dialectical imbalances, managing dialectics in a relationship is key. In the Communication Competence section of this chapter, we will discuss some techniques for how to better manage dialectics in relationships to increase relationship satisfaction.
Deteriorating Stage
In the deteriorating stage, relationships start to decline and may eventually be terminated. Typically, in this stage, people may start to avoid the other person, decrease communication with them, or engage in increased conflict (Verderber & Verderber, 2013). During this stage, Knapp’s Stages of Relational Interaction can help us better understand how relationships deteriorate and/or terminate. While the theory covers both stages of coming together and stages of coming apart, we only focus here on the latter: Differentiating, Circumscribing, Stagnating, Avoiding, and Terminating.
Differentiating
Differentiating is a process of disengaging or uncoupling; differences between the relationship partners are emphasized, and what was thought to be similar begins to disintegrate. Instead of working together, partners quickly begin to become more individualistic in their attitudes. Conflict is a common form of communication during this stage and oftentimes it acts as a way to test how much the other can tolerate something that may threaten the relationship.
Circumscribing
To circumscribe means to draw a line around something or put a boundary around it (Oxford English Dictionary Online, 2011). So when someone circumscribes, communication decreases and certain areas or subjects become restricted as individuals verbally close themselves off from each other. They may say things like “I don’t want to talk about that anymore” or “You mind your business and I’ll mind mine.”
Stagnating
When a relationship has stagnated, it has come to a standstill, as individuals basically wait for the relationship to end. Outward communication may be avoided, but internal communication may be frequent. The relational conflict flaw of mindreading takes place as a person’s internal thoughts lead them to avoid communication. For example, a person may think, “There’s no need to bring this up again, because I know exactly how he’ll react!” This stage can be prolonged in some relationships, and some people may linger here because they don’t know how to end the relationship, want to avoid potential pain from termination, or may still hope to rekindle the spark that started the relationship.
Avoiding
In this stage, as the name implies, when people engage in avoidance, they try to physically avoid each other. For example, you may decide not to go to a specific social gathering when you know that other person will be there. However, when actual physical avoidance cannot take place, people will simply avoid each other while they’re together and treat the other as if they don’t exist. When avoiding, the individuals in the relationship become separate from one another physically, emotionally, and mentally. When there is communication, it is often marked by antagonism or unfriendliness (“I just don’t want to see or talk to you”). [4] In addition to not spending time with one another, they both begin to avoid the other person’s needs and start to focus solely on themselves.
Terminating
The terminating of a relationship can occur shortly after a relationship begins or after twenty-year relational history has been established. Termination can result from outside circumstances such as geographic separation or internal factors such as changing values or personalities that lead to a weakening of the bond. Termination exchanges involve some typical communicative elements and may begin with a summary message that recaps the relationship and provides a reason for the termination (e.g., “We’ve had some ups and downs over our three years together, but I’m getting ready to go to college, and I want to be free to explore who I am.”). The summary message may be followed by a distance message that further communicates the relational drift that has occurred (e.g., “We’ve really grown apart over the past year”), which may be followed by a disassociation message that prepares people to be apart by projecting what happens after the relationship ends (e.g., “I know you’ll do fine without me. You can use this time to explore your options and figure out if you want to go to college too or not.”).
Finally, there is often a message regarding the possibility for future communication in the relationship (e.g., “I think it would be best if we don’t see each other for the first few months, but text me if you want to.”) (Knapp & Vangelisti, 2009). However, people also often engage in negative termination strategies such as yelling, blaming the other person, or ghosting, which is “the practice of suddenly ending all contact with a person without explanation (Dictionary.com).”


4.5.1: Key Concepts
Key Concepts
4.1 Hindu-Arabic Positional System
Exponents are used to represent repeated multiplication of a base.
- In arithmetic, exponents are computed before multiplication, division, addition, and subtraction. Computing an exponent is done by multiplying the base by itself the number of times equal to the exponent.
- The system of numbers currently used is the Hindu-Arabic system. Digits in this system take on values based on their place in the number. The place values are determined by multiplying the digit by 10 raised to the appropriate power.
- The expanded form of a Hindu-Arabic number is the sum of each digit times 10 raised to the exponent for that place value.
4.2 Early Numeration Systems
Historically, there have been many systems for numbering. One system is an additive system, in which symbols are repeated to express larger numbers. Another system is a positional system, in which the digits and their positions determine the quantity being represented.
- The Babylonian system was a combination of a positional and additive system. It used 60 as its base. Using that in the positional system makes it possible to convert between Babylonian and Hindu-Arabic numbers.
- The Mayan system was a combination of a positional and additive system. It used 20 as its base. Using that in the positional system makes it possible to convert between Mayan and Hindu-Arabic numbers.
- The Roman system was an additive system. Knowing what each symbol represents makes it possible to convert between Roman and Hindu-Arabic numbers.
4.3 Converting with Base Systems
The system we use is the base 10 system. Base 10 is not the only base that can be used. To use another base, one could start with a list of numbers in that base.
- To indicate that a number is written in a base other than 10, a subscript is appended to the end of the number. That subscript indicates the base for the number.
- Numbers written in a base smaller than 10 use the same symbols as base 10. However, when using bases larger than 10, the symbols A, B, C, … are used to represent digits larger than 9.
- To convert from a number written in a base other than 10 into a base 10 number, the number is written in expanded form and then that expression is computed.
- To convert a number from base 10 into another base, the base 10 number is repeatedly divided by the new base. The remainders when performing these divisions become the digits for the number in the new base.
- Common errors can be detected when performing base conversions.
4.4 Addition and Subtraction in Base Systems
Addition tables for bases other than 10 can be built using the same processes that are used in base 10, including using a number line.
- Addition in bases other than base 10 use the same processes as addition in base 10, but use the addition table for that base.
- Subtraction in bases other than base 10 use the same processes as subtraction in base 10, but use the addition table for that base.
4.5 Multiplication and Division in Base Systems
Multiplication tables for bases other than 10 can be built using the same processes that are used in base 10, including using repeated addition and the addition table for the base.
- Multiplication in bases other than base 10 use the same processes as multiplication in base 10, but use the multiplication table for that base.
- Basic division in bases other than base 10 use the same processes as basic division in base 10, where the missing factor process is used.


10.13: Putting It Together- Microsoft PowerPoint Intermediate Skills
Now that you know some of the more visual-based tricks in PowerPoint, let’s take a look at our opening list of possible presentation goals and match those with the skills you just learned.
- You want to show a clip from an advertising campaign. You can achieve this by inserting the video and even trim it to a shorter segment.
- You want to provide a visual introduction of newly hired employees. You can easily insert headshots of the new employees, and can even use the grouping and arranging options to make sure everyone gets equal billing in photo size and position.
Contributors and Attributions
CC licensed content, Original
- Putting It Together: Microsoft PowerPoint Intermediate Skills. Authored by : Shelli Carter. Provided by : Lumen Learning. License : CC BY: Attribution


11.5: References
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American Heart Association. (2011). Heartsaver first aid : Student workbook . Dallas, Texas: American Heart Association.
American Heart Association. (2014). 2014 Hands-only CPR fact sheet. Retrieved from http :// www . heart . org / idc / groups / heart public /@ wcm /@ ecc / documents / downloadable / ucm _441302. pdf
American Institute for Preventive Medicine. (2012). Burns. Retrieved from http://www.healthylife.com/online/He...SEA/Burns.html
Centers for Disease Control and Prevention. (2014a, May 19). Injury prevention. Retrieved from http://www.cdc.gov/healthyhomes/bytopic/injury.html
Center for Disease Control. (2014b, October 17). When & how to wash your hands. Retrieved from www.cdc.gov/handwashing/when-how-handwashing.html
Leahy, W., Fuzy, J., & Grafe, J. (2013). Providing home care: A textbook for home health aides (4th ed.). Albuquerque, NM: Hartman.
Mayo Clinic. (2014). Bruise: First aid. Retrieved from http://www.mayoclinic.org/first-aid/first-aid- bruise/basics/art-20056663
MedlinePlus (2014, July 22). Burns. In A.D.A.M. Medical Encyclopedia. Retrieved from http :// www . nlm . nih . gov / medlineplus / ency / article /000030. htm
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8.5: Life, Chemical Evolution, and Climate Change
By the end of this section, you will be able to:
- Outline the origins and subsequent diversity of life on Earth
- Explain the ways that life and geological activity have influenced the evolution of the atmosphere
- Describe the causes and effects of the atmospheric greenhouse effect and global warming
- Describe the impact of human activity on our planet’s atmosphere and ecology
As far as we know, Earth seems to be the only planet in the solar system with life. The origin and development of life are an important part of our planet’s story. Life arose early in Earth’s history, and living organisms have been interacting with their environment for billions of years. We recognize that life-forms have evolved to adapt to the environment on Earth, and we are now beginning to realize that Earth itself has been changed in important ways by the presence of living matter. The study of the coevolution of life and our planet is one of the subjects of the modern science of astrobiology .
The Origin of Life
The record of the birth of life on Earth has been lost in the restless motions of the crust. According to chemical evidence, by the time the oldest surviving rocks were formed about 3.9 billion years ago, life already existed. At 3.5 billion years ago, life had achieved the sophistication to build large colonies called stromatolites , a form so successful that stromatolites still grow on Earth today (Figure 8.15). But, few rocks survive from these ancient times, and abundant fossils have been preserved only during the past 600 million years—less than 15% of our planet’s history.
There is little direct evidence about the actual origin of life. We know that the atmosphere of early Earth, unlike today’s, contained abundant carbon dioxide and some methane, but no oxygen gas. In the absence of oxygen, many complex chemical reactions are possible that lead to the production of amino acids, proteins, and other chemical building blocks of life. Therefore, it seems likely that these chemical building blocks were available very early in Earth’s history and they would have combined to make living organisms.
For tens of millions of years after Earth’s formation, life (perhaps little more than large molecules, like the viruses of today) probably existed in warm, nutrient-rich seas, living off accumulated organic chemicals. When this easily accessible food became depleted, life began the long evolutionary road that led to the vast numbers of different organisms on Earth today. As it did so, life began to influence the chemical composition of the atmosphere.
In addition to the study of life’s history as revealed by chemical and fossil evidence in ancient rocks, scientists use tools from the rapidly advancing fields of genetics and genomics —the study of the genetic code that is shared by all life on Earth. While each individual has a unique set of genes (which is why genetic “fingerprinting” is so useful for the study of crime), we also have many genetic traits in common. Your genome , the complete map of the DNA in your body, is identical at the 99.9% level to that of Julius Caesar or Marie Curie. At the 99% level, human and chimpanzee genomes are the same. By looking at the gene sequences of many organisms, we can determine that all life on Earth is descended from a common ancestor, and we can use the genetic variations among species as a measure of how closely different species are related.
These genetic analysis tools have allowed scientists to construct what is called the “ tree of life ” (Figure 8.16). This diagram illustrates the way organisms are related by examining one sequence of the nucleic acid RNA that all species have in common. This figure shows that life on Earth is dominated by microscopic creatures that you have probably never heard of. Note that the plant and animal kingdoms are just two little branches at the far right. Most of the diversity of life, and most of our evolution, has taken place at the microbial level. Indeed, it may surprise you to know that there are more microbes in a bucket of soil than there are stars in the Galaxy. You may want to keep this in mind when, later in this book, we turn to the search for life on other worlds. The “aliens” that are most likely to be out there are microbes.
Such genetic studies lead to other interesting conclusions as well. For example, it appears that the earliest surviving terrestrial life-forms were all adapted to live at high temperatures. Some biologists think that life might actually have begun in locations on our planet that were extremely hot. Yet another intriguing possibility is that life began on Mars (which cooled sooner) rather than Earth and was “seeded” onto our planet by meteorites traveling from Mars to Earth. Mars rocks are still making their way to Earth, but so far none has shown evidence of serving as a “spaceship” to carry microorganisms from Mars to Earth.
The Evolution of the Atmosphere
One of the key steps in the evolution of life on Earth was the development of blue-green algae, a very successful life-form that takes in carbon dioxide from the environment and releases oxygen as a waste product. These successful microorganisms proliferated, giving rise to all the lifeforms we call plants. Since the energy for making new plant material from chemical building blocks comes from sunlight, we call the process photosynthesis .
Studies of the chemistry of ancient rocks show that Earth’s atmosphere lacked abundant free oxygen until about 2 billion years ago, despite the presence of plants releasing oxygen by photosynthesis. Apparently, chemical reactions with Earth’s crust removed the oxygen gas as quickly as it formed. Slowly, however, the increasing evolutionary sophistication of life led to a growth in the plant population and thus increased oxygen production. At the same time, it appears that increased geological activity led to heavy erosion on our planet’s surface. This buried much of the plant carbon before it could recombine with oxygen to form CO 2 .
Free oxygen began accumulating in the atmosphere about 2 billion years ago, and the increased amount of this gas led to the formation of Earth’s ozone layer (recall that ozone is a triple molecule of oxygen, O 3 ), which protects the surface from deadly solar ultraviolet light. Before that, it was unthinkable for life to venture outside the protective oceans, so the landmasses of Earth were barren.
The presence of oxygen, and hence ozone, thus allowed colonization of the land. It also made possible a tremendous proliferation of animals, which lived by taking in and using the organic materials produced by plants as their own energy source.
As animals evolved in an environment increasingly rich in oxygen, they were able to develop techniques for breathing oxygen directly from the atmosphere. We humans take it for granted that plenty of free oxygen is available in Earth’s atmosphere, and we use it to release energy from the food we take in. Although it may seem funny to think of it this way, we are lifeforms that have evolved to breathe in the waste product of plants. It is plants and related microbes that are the primary producers, using sunlight to create energy-rich “food” for the rest of us.
On a planetary scale, one of the consequences of life has been a decrease in atmospheric carbon dioxide. In the absence of life, Earth would probably have an atmosphere dominated by CO 2 , like Mars or Venus. But living things, in combination with high levels of geological activity, have effectively stripped our atmosphere of most of this gas.
The Greenhouse Effect and Global Warming
We have a special interest in the carbon dioxide content of the atmosphere because of the key role this gas plays in retaining heat from the Sun through a process called the greenhouse effect . To understand how the greenhouse effect works, consider the fate of sunlight that strikes the surface of Earth. The light penetrates our atmosphere, is absorbed by the ground, and heats the surface layers. At the temperature of Earth’s surface, that energy is then reemitted as infrared or heat radiation (Figure 8.17). However, the molecules of our atmosphere, which allow visible light through, are good at absorbing infrared energy. As a result, CO 2 (along with methane and water vapor) acts like a blanket, trapping heat in the atmosphere and impeding its flow back to space. To maintain an energy balance, the temperature of the surface and lower atmosphere must increase until the total energy radiated by Earth to space equals the energy received from the Sun. The more CO 2 there is in our atmosphere, the higher the temperature at which Earth’s surface reaches a new balance.
The greenhouse effect in a planetary atmosphere is similar to the heating of a gardener’s greenhouse or the inside of a car left out in the Sun with the windows rolled up. In these examples, the window glass plays the role of greenhouse gases , letting sunlight in but reducing the outward flow of heat radiation. As a result, a greenhouse or car interior winds up much hotter than would be expected from the heating of sunlight alone. On Earth, the current greenhouse effect elevates the surface temperature by about 23 °C. Without this greenhouse effect, the average surface temperature would be well below freezing and Earth would be locked in a global ice age.
That’s the good news; the bad news is that the heating due to the greenhouse effect is increasing. Modern industrial society depends on energy extracted from burning fossil fuels. In effect, we are exploiting the energy-rich material created by photosynthesis tens of millions of years ago. As these ancient coal and oil deposits are oxidized (burned using oxygen), large quantities of carbon dioxide are released into the atmosphere. The problem is exacerbated by the widespread destruction of tropical forests, which we depend on to extract CO 2 from the atmosphere and replenish our supply of oxygen. In the past century of increased industrial and agricultural development, the amount of CO 2 in the atmosphere increased by about 30% and continues to rise at more than 0.5% per year.
Before the end of the present century, Earth’s CO 2 level is predicted to reach twice the value it had before the industrial revolution (Figure 8.18). The consequences of such an increase for Earth’s surface and atmosphere (and the creatures who live there) are likely to be complex changes in climate, and may be catastrophic for many species. Many groups of scientists are now studying the effects of such global warming with elaborate computer models, and climate change has emerged as the greatest known threat (barring nuclear war) to both industrial civilization and the ecology of our planet.
Already climate change is widely apparent. Around the world, temperature records are constantly set and broken; all but one of the hottest recorded years have taken place since 2000. Glaciers are retreating, and the Arctic Sea ice is now much thinner than when it was first explored with nuclear submarines in the 1950s. Rising sea levels (from both melting glaciers and expansion of the water as its temperature rises) pose one of the most immediate threats, and many coastal cities have plans to build dikes or seawalls to hold back the expected flooding. The rate of temperature increase is without historical precedent, and we are rapidly entering “unknown territory” where human activities are leading to the highest temperatures on Earth in more than 50 million years.
Human Impacts on Our Planet
Earth is so large and has been here for so long that some people have trouble accepting that humans are really changing the planet, its atmosphere, and its climate. They are surprised to learn, for example, that the carbon dioxide released from burning fossil fuels is 100 times greater than that emitted by volcanoes. But, the data clearly tell the story that our climate is changing rapidly, and that almost all of the change is a result of human activity.
This is not the first time that humans have altered our environment dramatically. Some of the greatest changes were caused by our ancestors, before the development of modern industrial society. If aliens had visited Earth 50,000 years ago, they would have seen much of the planet supporting large animals of the sort that now survive only in Africa. The plains of Australia were occupied by giant marsupials such as diprotodon and zygomaturus (the size of our elephants today), and a species of kangaroo that stood 10 feet high. North America and North Asia hosted mammoths, saber tooth cats, mastodons, giant sloths, and even camels. The Islands of the Pacific teemed with large birds, and vast forests covered what are now the farms of Europe and China. Early human hunters killed many large mammals and marsupials, early farmers cut down most of the forests, and the Polynesian expansion across the Pacific doomed the population of large birds.
An even greater mass extinction is underway as a result of rapid climate change. In recognition of our impact on the environment, scientists have proposed giving a new name to the current epoch, the anthropocene , when human activity started to have a significant global impact. Although not an officially approved name, the concept of “anthropocene” is useful for recognizing that we humans now represent the dominant influence on our planet’s atmosphere and ecology, for better or for worse.


11.1: Introduction
A road is an identifiable route or path between locations. Nearly all roads are constructed in some way, typically by smoothing the natural landscape and often by paving. Roads serve as transportation routes, accommodating bicyclists, horses, vehicles, and pedestrians. Roads also provide access to property and provide right-of-way to other infrastructure systems such as pipelines or telecommunications cables. Reflecting on the ubiquity and importance of roads, there are many words denoting roadways, including: avenue, boulevard, court, drive, freeway, highway, parkway, street, etc.
Roadway construction dates back over 6,000 years. Early roads were paved with timber, brick and stone. The Roman Empire was noted for an extensive network of paved roadways, covering roughly 78,000 km in Europe and North Africa 2,000 years ago. Figure 11.1.1 shows a modern picture of former Roman road paved with stone and still in use in Syria.
Roads can be one-way, but most are divided in the center and accommodate two-way traffic. About a third of worldwide roadway traffic follows the convention of vehicles traveling on the left side of roadways, while two-thirds follow a right-side convention, including the United States (Figure 11.1.2).
Modern pavements are complex systems themselves, with multiple layers and drainage systems. Figure 11.1.3 illustrates a flexible (asphalt) pavement used for rural interstates in Idaho. The pavement has a surface layer of asphalt (six inches of plant mix bituminous pavement), a layer of asphalt treated permeable leveling course (two inches of ATPLC), gravel, a rock cap, a granular subbase, and a subgrade geotextile. The pavement is slanted to facilitate rain run-off.
Roadways are used for numerous purposes and by multiple types of vehicles. Table 11.1 shows vehicle miles travelled (in millions) for different types of vehicles and types of roadways. Limited access interstate roadways have significant amounts of traffic, but most traffic is carried on other types of roadways. Motorcycles, buses and truck traffic are significantly smaller than light duty vehicle traffic.
Table 11.1.1: U.S. Vehicle Miles Traveled by Type of Vehicle and Type of Roadway 2014.
| Roadway Type | Light-Duty Vehicle (million miles) | Motorcycles (million miles) | Buses (million miles) | Trucks (million miles) | All Vehicles (million miles) |
| Rural Interstate | 173,000 | 1,000 | 2,000 | 56,000 | 231,000 |
| Other Rural | 505,000 | 6,000 | 4,000 | 76,000 | 690,000 |
| Urban Interstate | 458,000 | 2,000 | 2,000 | 57,000 | 520,000 |
| Other Urban | 1,476,000 | 11,000 | 8,000 | 90,000 | 1,585,000 |
| Total | 2,711,000 | 20,000 | 10,000 | 279,000 | 3,026,000 |
Source: FHWA, Public Domain, Highway Statistics, https://www.fhwa.dot.gov/policyinfor...s/2014/vm1.cfm


29.9C: Myocardial Ischemia and Infarction
Ischemic heart disease is caused by reduced blood flow to the heart muscle, usually due to atherosclerosis, and can lead to a heart attack.
- Distinguish between the effects of myocardial ischemia and infarction on the heart
Key Points
- Ischemic heart disease (IHD), or myocardial ischaemia, is a disease characterized by ischaemia, or, reduced blood supply, to the heart muscle, usually due to coronary artery disease and myocardial infarction.
- Coronary artery disease is the narrowing of the heart arteries due to atherosclerosis, the deposition of fat on the walls. If these deposits come loose, they can cause a clot that will block blood flow to the heart muscle, causing a myocardial infarction.
- Symptoms of stable ischemic heart disease include angina, which is characteristic chest pain on exertion, and decreased exercise tolerance. Symptoms of myocardial infarction include acute chest pain, shortness of breath, nausea, vomiting, palpitations, sweating, and/or anxiety.
- Treatment of IHD is dependent on the underlying disease. Stable IHD may be treated with anti-angina drugs. Treatments for myocardial infarction include coronary angioplasty, treatment with “clot buster” medications, and coronary bypass, where blocked heart blood vessels are replaced.
- The phrase “heart attack” is sometimes used incorrectly to describe sudden cardiac death, which may or may not be the result of acute myocardial infarction.
Key Terms
- angioplasty : The mechanical widening of a narrowed or totally obstructed blood vessel generally caused by atheroma.
- ischemia : Local disturbance in blood circulation due to mechanical obstruction of the blood supply, such as by a narrowed artery or clot.
- angiography : A medical imaging technique in which an x-ray image is taken to visualize the inside of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers.
Acute myocardial infarction : The diagram depicts a myocardial infarction (2) of the tip of the anterior wall of the heart (an apical infarct) after occlusion (1) of a branch of the left coronary artery (LCA). Right coronary artery (RCA).
Ischemic heart disease (IHD), or myocardial ischaemia, is a disease characterized by ischaemia, or reduced blood supply to the heart muscle, usually due to coronary artery disease and myocardial infarction. Coronary artery disease is the narrowing of the heart arteries due to atherosclerosis, the deposition of fat on the walls. If these deposits come loose, they can cause a clot that will block blood flow to the heart muscle, causing a myocardial infarction. The risk increases with age, smoking, high cholesterol levels, diabetes, and high blood pressure, and is more common in men and those who have close relatives with ischaemic heart disease and a history of myocardial infarction. It is the most common cause of death in most western countries, and a major cause of hospital admissions.
Symptoms
Symptoms of stable ischemic heart disease include angina, which is characteristic chest pain on exertion, and decreased exercise tolerance.
Ischaemic heart disease may be present with any of the following problems:
- Angina—chest pain on exertion, in cold weather or emotional situations
- Acute chest pain—acute coronary syndrome, unstable angina or myocardial infarction
- Heart failure—difficulty in breathing or swelling of the extremities due to weakness of the heart muscle
- Heartburn
Atherosclerosis : This diagram depicts the progression of atherosclerosis in a blood vessel. In coronary artery disease, these atherosclerotic plaques build up in the coronary arteries and rupture may lead to ischemic heart disease and myocardial infarction.
Diagnosis
Ischemic heart disease is typically associated with an underlying specific heart disease.
In “stable” angina, chest pain with typical features occurs at predictable levels of exertion. Various forms of cardiac stress tests may be used to induce both symptoms and detect changes with electrocardiography (EKG), echocardiography (using ultrasound of the heart), or scintigraphy (using a radioactive marker to examine blood uptake by the heart muscle). If part of the heart seems to receive an insufficient blood supply, coronary angiography may be used to identify narrowing of the coronary arteries and suitability for angioplasty or bypass surgery.
Cardiac Stress Test : A patient undergoing a stress test. This test examines blood flow to the heart during exertion, and can be used as a diagnostic tool in ischemic heart disease, coronary artery disease, and heart failure.
Diagnosis of acute coronary syndrome and myocardial infarction generally take place in the emergency department when a patient presents with acute chest pain, combined with shortness of breath, nausea, vomiting, palpitations, sweating, and/or anxiety. An EKG is performed, looking for changes that are characteristic of a myocardial infarction. In the absence of these characteristic markers, heart damage is detected by cardiac markers in the blood that identify heart muscle damage. If there is no evidence of damage or infarction, a diagnosis of “unstable angina” is given. Depending on the risk assessment, stress testing or angiography may be used to identify coronary artery disease in these patients.
In patients with heart failure, stress testing or coronary angiography may be performed to identify and treat underlying coronary artery disease.
Causes
The disease process underlying most ischemic heart disease is atherosclerosis of the coronary arteries, which decreases blood flow to the heart muscle. Atherosclerosis is the thickening of the artery wall as a result of plaque formation, which is the accumulation of fatty materials such as cholesterol. Atherosclerosis reduces blood flow to the heart muscle, causing ischemia. When these plaques weaken, they can develops a tear, which forms blood clot that obstructs blood flow, causing a myocardial infarction.
Treatment
Treatment of ischemic heart disease is dependent on the underlying disease process. In stable IHD, antianginal drugs may be used to reduce the rate of occurrence and severity of angina attacks. Treatments for acute coronary syndrome and myocardial infarction include coronary angioplasty, treatment with thrombolysis “clot buster” medication, and coronary bypass, where narrowed blood vessels on the heart are replaced.
Various treatments are offered in people deemed to be at high risk of coronary artery disease. These include control of cholesterol levels in those with known high cholesterol, smoking cessation, and control of high blood pressure.